Valve mechanism for air-brake apparatus.



` PATBNTED JULY 14, 1908.

. E. A. PIERCE. VALVE MECEANISM EoE AIE BRAKE AEPARATUS..

API'PLIGATIONFILBD DEO. 17, 1906.

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VALVE MECEANISM EOE AIE- EEAIIE APPARATUS. APPLIoAIIoN FILED DEo.17.19o6.

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PATENTED yJULY 14, 1908.

VALVRMEGHANISM PORv AIR BRAKE APPARATUS.'

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UNITED sTATEs-j PATENT nien FRANKLIN A. PIERCE, OF WHEELING, WEST VIRGINIA, ASSIGNOR OF ONE-HALF TO JOHN Ti TRAVERS AND JOI-IN E. OSWALD, OF BELLAIRE, OHIO.

VALVE MECHANISM FOR AIR-BRAKE APPARATUS.

Application filed December 17, 1906. Serial No. 348,266.

To all whom it may concern:

Be it known that I, FRANKLIN A. PIERCE, a citizen of the United States of America, residing at Wheeling, in the county of Ohio and State of West Virginia, have invented certain new and useful Im rovements in Valve Mechanism for Air-Bra e Apparatus; and I hereby declare the following to be a full, -clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to make and use the same.

This invention relates to im rovements in valve-mechanism for air-bra e apparatus, and pertains more especially to an air-brake in which is employed a so-called triple-valvemechanism which controls the supply of air from the auxiliary reservoir to the brake-cylinder and also the exhaust from the brakecylinder.

The object of this invention is to provide air-brake apparatus wherein, althou h the auxiliary reservoir is recharged whi e the brake-cylinder is operating to apply the brake and hold the latter applied in and upon the partial or gradual application of the brake, full communication between the auxiliary reservoir and the brake-cylinder in the case of an emergencyA may be instantaneously established to at once fully apply the brake.

In the accompanyin drawings, Figure 1 is a side elevation large y in central vertical section of air-brake apparatus comprising valve-mechanism embodying 'my invention. In this figure the pistons and valves of the said valve-mechanism are shown in their normal and brake-releasing position. Fig. 2 is a side elevation, mostly in central Vertical section, showing the said pistons and valves in their brake-ap lying position in the partial or gradual appIication of the brake. Fig. 3 is a vertical section on line 3-3, Fig. 1, looking in the direction indicated by the arrow.

Fig. 4 is a side elevation, mostly in central vertical section, illustrating the position of the aforesaid valves andk pistons upon the instantaneous application of the brake.

Referring to the drawings, A indicatesthe valve-casing of so-called triple-valve-mechanism. The casing A is provided interiorly with a chamber 10. A piston B snugly fits within and is adapted to move endwise of the chamber 10. The chamber 10 is arranged horizontally, and the valve-casing A is vpro- Specifcaton of Letters Patent.

' the travel ofthe valve b.

Patented July 14, 1908.

vided interiorly and below the said chamber with a port 12 which communicates at its upper end with the outer end ofthe chamber 10 and at its lower end with a horizontally arranged pipe O. The lport 12 constitutes the train-pipe-pressure in et of the chamber 10.

he Valve-casing A is provided at the inner end of the chamber 10 with a valve-seat 13 which is arran ed horizontally and parallel with the traveI of the piston B, and a correspondingly arranged single-ported slidevalve b is mounted on or engages the seat 13 and rigid or o eratively connected with the piston B, sai valve being provided in its under side and next to the seat 13 with a port 14.

The valve-casing A is provided interiorly with -two ports 15 and 16 which extend from the seat 13 and are spaced longitudinally of The ort 15 communicates with the pipe D emp oyed in conducting reservoir-pressure to the brake-cylinder (not shown). The pi e D constitutes therefore the brake-cylinder-supply pipe. The port 16 communicates with the external atmosphere and therefore constitutes an exhaust-port.

The valve-casin A is rovided interiorly and next external y of tie valve b with a chamber 17 which communicates with the chamber 10 at the inner end of the latter and extends to the Valve-seat 13y at the free end of the valve in any position of the valve.

E indicates the auxiliary reservoir which is provided with an outlet e which communicates 4with the chamber 17 and consequently with the chamber 1() at the inner end of the latter, and f represents a ipe which communicates with and is emplbyed in supplying trainpipepressure to the reservoir. The reservoir-outlet e, the chamber 17 and the port 15 forma passageway adapted to estabish communication between the reservoir E and the pipe D, and the ports 14, 15 and 16 I form a passageway adapted to exhaust the pipe D, and the valve b controls continuity in the said passageways.

The iston B is arranged to operate between t e ort 12 and the reservoir-outlet c, and the reliative arrangement of the parts is such that when the piston B is in its normal position at the inner end of the chamber 10, as shown in Fig. 1, communication between the reservoir E and the pipe D is interrupted and communication between the said pipe D and the exhaust-port 16 established so that the pressure preparatory to the release of the brake and by the reservoir-pressure preparatory to the application ofthe brake.

G represents a pipe for supplying trainpipe-pressure, which pi e has its discharging end arranged in line enc wise with and a suitable distance from the pipe C, and a valvecasing H is interposed between and attached to the said pipes C and G. The valve-casing H is provided interiorly and a suitable distance above the adjacent ends of' the pipes C and G with a vertically arranged chamber 20. A piston K snugly fits within and is adapted to move endwise of the chamber 20. The upper or outer end wall of the chamber 2() is provided with a port 22 -which constitutes the iiuid-outlet and train-pipe-pressure inlet of the said chamber.

The valve-casing H is Aprovided interiorly with a vertically arranged bore 23. The bore 23 is arranged centrally of the lower end of and connects with the chamber 20. The bore 23 extends downwardly from the chamber 2O to a point a suitable distance below the adjacent ends of the pipes C and G and is snugly engaged by a double-ported slidevalve c which is movable endwise of the said bore and is rigid or operatively connected with the piston K. The bore 23 communicates at its lower end,-that is, at the free end oi' the valve 76,-with a port 24 which is arranged centrally of the said end of the said bore and constitutes the pressure-inlet and fluid-outlet of the said bore during the operation of the valve c. The port 24 is in communication with the pipe f, and consequently the bore 23 is in communication at the free end of the valve cwith the reservoir E.

The valve c is provided centrally between its ends with a horizontally arranged port 25 which extends transversely of and through the valve. The valve 7c is provided in one side thereof centrally between the port 25 and the free end of the valve with a port 26 which extends longitudinally of the valve a suitable distance.

The valve-casing H is provided with two horizontally arranged ports 27- and 28 which are arranged in line endwise at opposite sides respectively of the travel of the valve 7c and communicate with the pipes Cr and C respectively.

The valve-casing H is provided interiorly with a way 30 which communicates at one end with the valve-port 26 and. at its other end with the valve-casing-port 23. '.lhe. way 3() is provided with a suitablyapplied and suitably confined valve l which controls continuity in the said way and is arranged to open in the direction required to permit the passage of fluid from the valve-port 26 to the valve-casing-port 23. The valve-port 26 is long enough to communicate with the valvecasing-port 30 in any position ol the valve.

The valve-casing H is provided interiorly adjacent the way 3() with another way 32 which at one end connects and is adapted to communicate withthe valve-port-conneeting end of the way 3() at a point between the valve I and the valve-port 26, and at its other vend is connected and communicates with the bore 23 at the free end of the valve c and with the pipef. The way 32 is provided interiorly with a valve J which controls continuity in the said way and is arranged to open in the direction required to' permit the passage of pressure from the way 30 at a point between the valve l and the valve-port 26 to the bore 23 and pipef.

Thevalve-casing H is provided interiorly of its upper end, between the chamber 2() and the valve-casing A, with a horizontally arranged chamber 40. A piston L snugly 'its within and is adapted to move endwise of the chamber 40. A way 42 communicates at one end with the chamber 4() centrally of the outer end of' the said chamber and communicates at its other end with the port 24, way 32 and pipef. The chamber 4() is consequently in communication at its outer end with the reservoir E. The valve-casing H is )rovided above and exteriorly ot the chamber 2O with a valve-seat 43 which is arranged horizontally and parallelwith the travel of the piston L, extending from the chamber to and over the chamber 20. A correspondingly arranged four-ported slidevalve l is mounted on or engages the seat 43 and is rigid with or operatively connected with the piston L, said valve being provided with three ports 44, 45 and 46 which extend vertically through the valve, and having an exhaust-poit 47 which is arranged between the outer and central vertical ports 44 and 45 and extends from the valve-seat 43 to one side of the valve where it is adapted to communicate (see Fig. 3) through an exhaust-port 49 formed in the valve-casing ll with the external atmosphere.

The valve-casing H is provided interiorly and next externally of the valve. Z with. a chamber 48 which communicates with thel chamber 4() at the inner end of the latter and extends to the valve-seat 43 at the l'ree end of the said valve in any position of the, valve.

TWO ways 50 and 52 are formed in thc valve-casing H at opposite sides respectively of the chamber 20. The way 50 communicates at one end with the chamber 48 at lthe outer end of the chamber and communicates at its other end with the valvecasing-port 27. The way 52communicates at one end with the valve-port 46 and at its other end with the valve-casing-port 28. A valve m contained within the way 52 controls continuity in the said way and is arranged to open in the direction of the valveport 46 to permit the passage of fluid through the said way from the valve-casingport 28 toward the chamber 48 and into the latter through the valve-port 46. The ort 46 extends longitudinally of the valve far enough to maintain communication between the way 52 and the chamber 48 in any position of the valve. The chamber '48. establishes communication between the chamber 40 and the way 50.

A stop for limiting the movement of the valve Z and connected piston L in the direction ofthe outer end of the chamber 48 is provided and preferably formed by the head r of a horizontally arranged and endwise shiftable stem R which extends through a stuffing-box 55 with which the valve-casing I-I is provided. around the said stem. The outer end of the stem R is screw-threaded externally, and a correspondingly threaded nut 56 is mounted on the said end of the said stem at the outer end of the stuffing-box 55. The nut 56 forms a sto to limit the inward movement of the stoporming head r of the stem R, and'a spiral spring 9c is mounted and confined on the stem R between the head r and the inner end of the stuiin'g-boX 55, which spring acts to retain the said stem in its inner and normal position.

Preferably a spring y is confined between the top of the valve Z and the top wall of the chamber 48 and acts to retain the valve in roper engagement with the valve-seat 43.

t will be observed that the valve-casingport 27, valve-port 25, valve-casingort 28', ipe C and port 12 are instrumenta in the formation of a passageway between the train-pressure-supply pipe G' and the chamber 10, and continuity in the said passageway is controlled by the valve rThe valvecasing-port 27, way 50, chamber 48, valveport 44 and valve-casingort 22 are instrumental in the formation cfa passageway be- -tween the train-pressure-supply pipe G and the chamber 20, and continuity 1n the said passageway is controlled -by the valve l. The valve-casing-portu27, wa 50, chamber 48, valve-Jort 46, way 52, va ve-casing-port 28, pipe and ort 12 are instrumental in the formation o' a assageway between the train-pressure-supp y pipe G and the chamber 10, and continuity in the said passageway is controlled by the valve m.A The valve-casing-port 27, the valve-port26, the

valve-port-connecting end of the way 30, the way 32, and the way 42 are instrumental in the formation of a assageway between the trainressure-supp y pipe G and the outer end o the chamber 40, and continuity in the said passageway is controlled by the valve k. The valve-casing-port 27, valve-port 26, the valve-port-connecting end of the way 30, the Way 32 and the pipe f are instrumental in the formation of a passageway between the train-pressure-supply-pipe G and the auXilairy reservoir, and continuity in the said passageway is controlled by the valve k.

In the normal and brake-releasing position of the piston B and connected valve l),

(as shown in Fig. 1) the piston K is in its l normal position at the lower or inner end of Ithe chamber 2() and the valve 7c is in position Vin the valve-casing.

4 In the 4normal and brake-releasing position of the-pistons K and L and connected valves the chamber 20 is in communication through the 4valve-casing-port 22, valve-port 44, chamber 48, way 50 and valve-casingport 27 with the train-pressure-supplyv pipe G, and the chamber 10 is in communication through the port 12, pipe C, valve-casingport 28, valve-port 25 and valve-casing-port 27 with the said train-pressure-supply pipe.

A reduction in the train-pipe-pressure results in the application of the brake. To partially or gradually apply-the brake the train-pipe-pressure is irst reduced just enough to move the valve Z into contact with the stop r and this reduction in the trainpipe-pressure obviously results in a reduction of the air-pressure within the chambers 10, 20 and 40 so as to result in the actuation of the pistons B, K andL and connected valves into a brake-applying position, as shown in Fig. 2, by the reservoir-pressure against the piston B next the valve b, against the face of the piston L at the outer end of the chamber 40 and against the lower or free end of the valve 7c. Upon the actuation of the pistons and connectedvalves to partially or gradually ap ly the brake, as

shown in Fig. 2, the valve is in contactwith munication with the chamber 20, and with its exhaust-port 47 in communication with the exhaust-port 49 in the valve-casing, and the valve lc is in position with its port 25 out of communication with the valve-casingports 27 and 28 and with its port 26 establishing communication between the valvecasing-port 27 and the way 30. Consequently while the brake is being held applied the auxiliary reservoir E may be recharged by pumping air into the train-pressuresupp y pipe G and in thus recharging the reservoir air under pressure passes from the train-pipe-pressure supply-pipe G through the valve-easing-port 27, valve-port 26, way 30, way 32 and pipe f into the reservoir. Of course during the recharging of the reservoir E the air-pressure at both ends of the chambers 10 and 40 become equal. Upon a partial application of the brake, as shown in Fig. 2, a'further and full application of the brake is had by a further reduction in the trainpressure-supply pipe to the extent required to actuate the stop r by the valve Z against the action of the spring far enough to bring the valve-port 45 into communication through the valve-casing-port 22 with the chamber 20 and thereby effect a further reduction of the pressure in the passageway connecting the chamber 48 with the chamber 10 and formed, as already indicated, by the valve-port 46, way 52, valve-casing-port 28, pipe C and port 12.

For a full and instantaneous application of the brake as required in the ease of an emergency, the full travel of the pistons B and L and connected valves is at once effected without moving the piston K and connected valve 7c by instantaneously reducing the train-pipe-pressure to such an extent that the valve Z is at once brought from the position shown in Fig. 1 into position to bring its port 45 into communication through the valve-casing-port 22 with the chamber 20, as shown in Fig. 4.

It will be observed therefore that my valve-mechanism may be operated to fully and instantaneously apply the brake as well as to partially and gradually apply the brake and permit of a recharging of the auxiliary reservoir during and upon the partial or gradual application of the brake.

Referring again to the movement of the pistons B, K and L to partially or gradually apply the brakes, 1 would here remark that the construction and arrangement of the parts are such that the piston B in its brakereleasing position has enough less surface exposed to the auxiliary-pressure than to the train-pipe-pressure that the train-pipe-pressure in the chamber 10 is a few pounds greater than the pressure in the chamber 17, whereas the piston L has an equal pressure upon both faces thereof, so that a reduction of, for instance, one-half pound pressure in the train-pipe will cause the piston L to move so as to place port 47 over port 22, resulting in the elevation or movement ol the piston K to a retaining and recharging position. 1n other words, because the pressure in the chamber 1() is somewhat greater than in the chamber 17 in the brake-releasing position of the piston B the said reduction of pressure in the train-pipe will result in the movement of the pistons L and K before the piston B begins to move into its brake-applying position.

What I claim is 1. In valve-mechanism for air-brake apparatus, the combination, with the auxiliary reservoir having an outlet; the brake-cylinder-connecting pipe g a pipe for supplying train-pipe-pressure, and a valve-easing previded interiorly with a chamber having a train-pipe-pressure-inlet, a piston snugly i'itting within and movable endwise of the chamber and in its normal and brake-releasing position arranged a suitable distance from the said inlet, which piston is arranged between and exposed to the train-pipe-pressure and reservoir-pressure and adapted to be actuated by the reservoir-pressure and train-pi e-pressure in opposite directions respective y a slide-valve operatively connected with the piston, and a seat for the valve, the valve and valve-casing being ported and ehambered as requiredV to exhaust the brakecylinder-connecting pipe in the normal and brake-releasing position of the piston and to establish communication between the outlet of the auxiliary reservoir and the said pipe upon the actuation of the piston to the extent required by the reservoir-pressure, of means whereby, upon a ieduction of the train-pipepressure to )artially or gradually apply the brake, the aforesaid piston being actuated by the reservoir-pressure and the reservoir is recharged during and upon the said actuation of the piston by the reservoir-pressure.

2. In valve-mechanism for air-brake apparatus, the combination, with the auxiliary reservoir having an outlet, the brake-cylinder-connecting pipe; a pipe for supplying train-pipe-pressure, and a valve-casing provided interiorly with a chamber having a train-pipe-pressure inlet, a piston snugly litting Within and movable cndwise ol the said chamber and in its normal and lnalw-releasing position arranged a suitable distance from the said inlet, which. piston is arranged between and exposed to the trai]i-pipe-pressure and reservoir-pressure and adapted lo be actuated by the reservoir-pressure and train-pipe-piessure in opposite directions respectively g a slide-valve operatively connected with the piston; a seat for the said valve, and a chamber formed next externally of the valve and extending from the lirst-inentioned chamber to the valve-seat at the free end of the valve and being in communication with the reservoir-outlet, the valve and valve-casing bein ported as `required to exhaust the and brake-releasing position of the piston and to establish communication between the second-mentioned chamber and the said pipe upon the actuation of the piston to the extent required by the reservoir-pressure, of means instrumental in rechargin the reservoir from the train-pressure-su pIy pipe during and upon the actuation o the aforesaid piston-by the reservoir-pressure upon a reduction ofthe trainipe-pressure to partially or gradually apply t e brake.

3. In air-brake a paratus, the auxiliary reservoir; the brale cylinder connecting pipe; al pipe for supplying train-pipe-pressure; a chamber 10 having a train-pi e-pressure inlet; a piston snuglyl fitting wit in and movable endwise of the said chamber and in its normal and brake-releasing position arranged a suitable distance from the said inlet, which iston is arranged between and exposed to t e trainipe-pressure and reservoir-pressure and a apted to be actuated by the reservoir-pressure and train-pipe-pressure in opposite directions respectively; means whereby the brake-cylinder-connecting pi e is supplied with air under pressure from t e reservoir upon the actuation of the piston to the extent required by the reservoir-pressure and is exhausted upon the actuation of the piston by the train-pipe-pressure, and means instrumental in recharging the reservoir from the train-pipe-pressuresupply pipe during and upon the actuation of the aforesaid piston by the reservoir-pressure upon a reduction of the trainipe-pressure to partially or gradually apply t e brake.

4. In valve-mechanism for air-brake apparatus, the combination, with the auxiliary reservoir; the brake cylinder connecting pipe g a pipe for supplying train-pipe-pressure a valve casing provided interiorly with a chamber having a trainipe-pressure inlet; a piston snugly fitting wit in and movable endwise of the said chamber and in its normal quired to exhaust the brake-cylind'er-con-- necting pipe in the normal and brake-releasing position of the piston and to establish communication between the second-mentioned chamber and the said pipe upon the actuation of the piston to the extent required by the reservoir-pressure, of means whereby full communication between the brake-cylinder-supply pi e and the reservoir may be instantaneous y established by a sudden reduction of the train-pipe-pressure to the extent required and whereby by a reduction of the trainipe-pressure to gradually establish the sai communication yto partially or gradually apply the brake the aforesaid piston is actuated by the reservoir-pressure and the reservoir is recharged during and upon the said actuation of the piston by the reservoirressure.

5. n valve-mechanism for air-brake apparatus, the combination, with the auxiliary reservoir; the brake-cylinder-supply pipe; a pipe for supplying train-pipe-pressure, and a valve-casing provided interiorly with the following a chamber having a train-pipe- -pressure inlet; a iston snugly fitting within and movable en wise of the said chamber and in its normal and brake-releasing position arranged a suitable distance from the said inlet, which iston is arranged between and exposed to t e train-pipe-pressure and reservoir-pressure and adapted to be actuated by the reservoir-pressure and train-pi epressure in opposite directions res ectivell) a slide-valve operatively connecte with the iston; a seat for the valve, and a chamber formed next externally of the valve and extendin from the first-mentioned chamber to the va ve-seat at the free lend of the valve and being in communication with the reservoir, the valve and valve-casing being orted as required to exhaust the brake-cy indersupply pipe in the normal and brake-releasing position of the piston and to establish communication between the second-mentioned chamber and the said pipe upon the actuation of the piston to the extent required by the reservoir-pressure, of a valve-casing interposed between the traini e-pressure-supply pipe and the aforesaid 1n et and provided with the chambers 20, 40 and 48, the bore 23, the ports 22, 24, 27, 28 and 49, and the ways 30, 32, 42, 50 and 52; the pistons K and L; the valve k having the ports 25 and 26; the Y valve l having the ports 44, 45, 46 and 47,

and the valves I, J and m, all arranged and and movable en wise of the said chamber and in its normal andbrake-releasing position arranged a suitable distance from the said inlet, which iston is arranged between and exposed to t e train-pipe-pressure and reservoir-pressure and adapted to be actuated by the reservoir-pressure and train-pipepressure in opposite directions respectively; a slide-valve o eratively connected with the iston; a seat or the valve, and a chamber formed. next externally of the valve and extending from the first-mentioned chamber to the valve-seat at the `free end of the valve and being in communication with the reser voir, the valve and valve-casing being orted as required to exhaust the brake-cylinderconnecting pipe in the normal and brake-releasing position of the piston and to establish communication between the second-mentioned chamber and the said pipe upon the actuation of the piston to the extent required by the reservoiraressure, of a second valvecasing interposeil between the train-pipepressure-sup ly pipe and the aforesaid inlet and providec with the chambers 20, 40 and 48, the bore 23, the ports 22, 24, 27, 2S and 49 and the ways 30, 32, 42, 50 and 52; the pistons K and L; the valve k having the ports 25 and 26; the valve l having the ports 44, 45, 46 and 47; the valves lf, J and m,- the shiftable stop r and the spring a, all arranged and operating substantially as shown and described,

7. In valve-mechanism for air-brake apparatus, the combination, with an auxiliary reservoir E a brale-cylinder-supply pipe D; a pipe G for supplying train-pipe-pressure, and a valve-casing A provided interiorly with the following z a chamber 10 having a trainpipe-pressure inlet; a piston B within the said chamber; a slide-valve I) operatively connected with the piston; a seat for the valve, and a chamber 17 formed next externally of the valve and extending from the first-mentioned chamber to the valve-seat at the free end of the valve and being in communication with the reservoir, the valve and valve-casing being ported as required to exhaust the brake-cylinder-supply pipe in the normal and brake-releasing position of the piston and to establish communication between the second-mentioned chamber and the said pipe upon the actuation of the piston to the extent required by the reservoir-pressure, of a valve-casing H interposed between the train-pipe-pressure-supply pipe and the aforesaid inlet and comprising` a chamber 20 having a combined inlet and outlet 22 at one end; a piston K within the last-mentioned chamber; a bore 23 connecting at one end with the other end of the last-mentioned chamber, which bore is in communication at its other end with the auxiliary reservoir; a double-ported slide-valve lc engaging the said bore and operatively connected with the lastmentioned piston, which valve is provided with a transverse port 25 and a side port 2G; two ports 27 and 2S formed in the secondmentioned valve-casing at opposite sides respectively of the travel of the double-ported valve and comnnmicating the one with the train-pipe-pressure-supply pipe and the other with the inlet of the piston-containing chainber of the first-mentioned valve-casing; a slide-valve-seat formed within the secondmentioned valve-casing externally of the aforesaid. piston-containing chamber of the said valve-casing; a chamber 4() arranged at one end of the last-mentioned valve-seat and. in communication at its outer end with the aforesaid. bore at the free end of the doubleported valve and with the reservoir; a piston L within the lastmentioned chamber; a slide-valve l engaging the last-,nientimud seat and operatively connected with the lastmentioned piston; a suitabhv valved waiv 52 communicating at one end with the trainpipe-pressure-supply pipe and at its other end with the aforesaid inlet ol the pistoncontaining chamber of the -lirst-mentioned valve-casing; a suitably valved way 3() communicating at one end with the last-inentioned inlet and at its other end with the side-port of the double-ported valve in either position of the latter; a suitably valved wa)Y 32 arranged to receive air under pressure from the said side port and communicating with the reservoir and with the aforesaid bore at the free end of the double-ported valv x and with the second-mentioned piston-con tainingr chamber Of the second-mentioned valw-easing at the outer end of the said chamber, and a passage-way establishing communication with the last-mentioned piston-containing chamber and the train-pressure-supply-pi pe, and the valve connected with the piston. in the last-mentioned chamber and the second-nientioned valve-casing being ported as required to exhaust the 'first-mentioned piston-containing chamber of the said valve-casing during the gradual actuation of the last-nientioned piston by reservoir-pressure and to su )ply train-pipe-pressure to the combined in et and outlet of the said chamber upon the actuation of the said piston by train-pipepressure, all arranged to operate substantially as and for the pur )ose set forth.

In testimony whereof, sign the foregoing specification, in the presence of two witnesses.

FRANKLIN A. PIERCE. Witnesses JAMES C. EDWARDS, J. E. OswiiLD. 

